How Hacker News ranking really works: scoring, controversy, and penalties
http://www.righto.com/2013/11/how-hacker-news-ranking-really-works.html

The Evolution Of Hacker News
https://techcrunch.com/2013/05/18/the-evolution-of-hacker-news/

Reddit sorting code
https://github.com/reddit-archive/reddit/blob/master/r2/r2/lib/db/_sorts.pyx

Revealed: US spy operation that manipulates social media
https://www.theguardian.com/technology/2011/mar/17/us-spy-operation-social-networks

5G Got me Fired
https://medium.com/@dvorak/5g-got-me-fired-ce407e584c4a

Learning to rank
https://en.wikipedia.org/wiki/Learning_to_rank#Evaluation_measures

How Not To Sort By Average Rating
https://www.evanmiller.org/how-not-to-sort-by-average-rating.html

Wilson score interval
https://en.wikipedia.org/wiki/Binomial_proportion_confidence_interval#Wilson_score_interval

reddit’s new comment sorting system
https://redditblog.com/2009/10/15/reddits-new-comment-sorting-system/

Markov Chains Explained Visually
http://setosa.io/ev/markov-chains/

An algorithmic framework for performing collaborative filtering
https://dl.acm.org/citation.cfm?id=312682

Item-based collaborative filtering recommendation algorithms
https://dl.acm.org/citation.cfm?id=372071

FunkSVD
http://sifter.org/~simon/journal/20061211.html

Probabilistic Matrix Factorization
https://papers.nips.cc/paper/3208-probabilistic-matrix-factorization.pdf

Bayesian Probabilistic Matrix Factorization using Markov Chain Monte Carlo
https://www.cs.toronto.edu/~amnih/papers/bpmf.pdf

Algorithms for Non-negative Matrix Factorization
https://papers.nips.cc/paper/1861-algorithms-for-non-negative-matrix-factorization.pdf

Learning the parts of objects by non-negative matrix factorization
http://www.columbia.edu/~jwp2128/Teaching/E4903/papers/nmf_nature.pdf

Restricted Boltzmann Machines for Collaborative Filtering
https://www.cs.toronto.edu/~rsalakhu/papers/rbmcf.pdf

AutoRec: Autoencoders Meet Collaborative Filtering
http://users.cecs.anu.edu.au/~u5098633/papers/www15.pdf

Collaborative Filtering for Implicit Feedback Datasets
http://yifanhu.net/PUB/cf.pdf